Manufacture of plates for artificial teeth.



No. 829,997. PATENTED SEPT. 4, 1906. A. OLLBNDORPF. MANUFACTURE OF PLATES FOR ARTIFICIAL TEETH.

APPLIUATION FILED FEB- 28, 1905.

UNITED STATES PATENT OFFICE.

MANUFACTURE OF PLATES FOR ARTIFICIAL TEETH.

Specification of Letters Patent.

Patented Sept. 4, 1906.

Application filed February 28, 1905. Serial No. 247,819.

To all whom it may concern/.-

Be it known that I, ARTHUR OLLENDORFF, a subject of the King of Prussia, residing at Breslau, in Germany, have invented certain new and useful Improvements in the Manufacture of Plates for Artificial Teeth, of which the following is a specification.

This invention relates to improvements in the manufacture of plates for artificial teeth, reference being made to the annexed drawings, in which I Figure l is a plan, and Figs. 2 and 3 sections, illustrative of the improved method.

It is known that metallic plates for artificial teeth have over those of caoutchouc the advantages of greater convenience and durability, but the manufacture of such plates is at present invariably effected by stamping them out of metal plates, the teeth and clamps being subsequently soldered on. The reason for the adoption of this method of manufacture lies in the fact that the methods which have hitherto been known for casting metallic plates are still more inconvenient than that of stamping, while they do not obviate the necessity for soldering on the teeth and clamps. To these causes is due that metallic plates have not hitherto entirely superseded those of caoutchouc, notwithstanding the advantages of the former. United States Patent No. 633 ,222 relates, for instance, to a method for casting aluminium plates for artificial teeth. According to the method described in the specification of this patent a wax model or pattern is placed, for the purpose of producing the mold, in a twopart flask containing fireproofmaterial, the flask being thereupon opened and Washed out with hot water for the purpose of removing the wax. In order to remove such traces of wax as remain in the mold after the washing process, the flask is thereupon placed in a suitable furnace, in which the wax is burned out.

Accordin to the p esent invention, plates for artificia teeth ar e produced by casting with wax models in a manner similar to that adopted for casting delicate metal ornaments and the like. This method has, over that described in the patent referred to, the advantage that the washing out of the wax is rendered unnecessary, the said Wax being entirely removed by a burning process; The improved method also has the advanta e that it allows of dispensin with flasks ma e in parts, the use of such asks being inconvenient, inasmuch as the parts cannot be readjusted in exactly the original position af ter they have been separated for the purpose of washing out the wax. The'flasks used according to the present invention allow of producing molds for the production of which flasks consisting of more than two parts would be required according to the older method, and the cast can therefore be made to include the necessary clamps and to constitute not only the plate, but the complete outfit required, which may consist of gold, silver, or other metal. This was hitherto not practicable.

According to the present invention an impression of the patients gums and mouth is made in the usual way and with the known material. From this im ression a model a is thereupon made in the nown manner with the. aid of a suitable mixture of gypsum and fireproof material, the said model being adapted to serve as part of the mold. .The plate I) is thereupon modeled in wax upon the gypsum model, and the wax model resultlng therefrom, with or without the gypsum.

model, is embedded in a mixture of gypsum and fireproof material 0, placed in allask of clay (I or the like. The teeth a need not be provided with a protective plate. Gates of colo hony or wax for themolten metal are mad in the mold in the usual manner, and. air-holes are provided, if required. When the gypsum, with its admixture of fireproof material, has become dry, it is subjected to such a degree of heat in the flask that the wax is by this means completely evaporated and the mold for casting produced. During the casting of the plate the teeth are very liable. to become cracked. It has been found that in order to prevent this the mold with -the teeth therein must be maintained for a considerable time at red heat, but at a temperature below the melting-point of the metal used. Care must be taken not to heat the mold for too long or too short a period or at a lower or higher temperature-for instance, at the temperature at which the metal meltssince the has been foun'd in almost all cases to result in the cracking of the teeth. For this reason no satisfactory result has been obtained by using the same furnace for heating the mold and fusing the metal. A separate furnace is therefore preferably used for the latter purpose. It has also been found that to prevent the cracking of the teeth the mold must not be removed from the heatingfurnace for the purpose of making the cast that is to say, the cast must be made in the heating-furnace itself. This may be due to the fact that the' mold becomes slightly cooled immediately on its removal from the heating-furnace and that the reduction of temperature causes the teeth to crack. The method of manufacture above described is more simple and cheap than any which has hitherto been devised. Any suitable metal or alloy can be used for making the plates. The method can also be conveniently combined with the use of caoutchouc, enamel, and gold and employed for making single teeth, crowns, and bridges.

What I claim as my invention, and desire to secureby Letters Patent of the United States, is

1. A method for the manufacture of metallie plates for artificial teeth consisting in producing an impression of the mouth, making from said impression a plaster model, modeling the plate in wax upon said plaster model,

embedding the Wax model in fireproof material to form a mold, embedding the teeth in the wax model and mold, heating the mold in a furnace by which the wax is completely evaporated and casting the plate in said mold, substantially as described.

2. A method for the manufacture of metallic plates for artificial teeth consisting in produeing an impression of the mouth, making from said impression a model consisting of a mixture of gypsum and fireproof material, modeling the plate in Wax upon said gypsum model, embedding the wax model with the gypsum model in a mixture of gypsum and fireproof material within a flask to form a mold, embedding the teeth in the wax model and mold, allowing the mold to dry, heating the mold and flask in a furnace to a temperature suil'icient to completely evaporate the wax casting the plate in the mold in said furnace and maintaining the mold for a oonsiderable time at a red heat but below the melting temperature of the metal substantially as described.

In witness whereof I have signed this specification in the presence of two witnesses.

ARTHUR OLLENDORFF.

Witnesses VVILHELM KI'JPPA, EnNs'r KATZ. 

